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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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    <!-- 把数组中的每一个元素用&拼接到一起并输出 -->
    <script>
        var arr = [1, 2, 3, 4, 5];
        var str = arr.join('&');
        console.log(str);
    </script>
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